/// <summary>
/// 按比例，获取红蓝两色之间的渐变色，中间使用白色过渡，适用于表现气温、负载等
/// </summary>
/// <param name="scale">比例, 0-1之间的数据</param>
/// <returns></returns>
public static Color getColorBetweenRedBlue(double scale)
{
float h, s;
//Color c = System.Drawing.Color.FromArgb(0x10, 0x00, 0xDC);
if (scale > 0.5)
{
float ss = (float)(scale - 0.5) * 2;
h = 60f - 60f * ss;
s = 255f * ss;
}
else
{
float ss = (float)scale * 2;
h = 240 - 60 * ss;
s = 255f * (1 - ss);
}
System.Drawing.Color dc = HSBColor.FromHSB(new HSBColor(255, h * 255 / 360, s, 255));
Color color = Color.FromArgb(dc.A, dc.R, dc.G, dc.B);
return(color);
}
public static Color FromHSB(HSBColor hsbColor)
{
float r = hsbColor.b;
float g = hsbColor.b;
float b = hsbColor.b;
if (hsbColor.s != 0)
{
float max = hsbColor.b;
float dif = hsbColor.b * hsbColor.s / 255f;
float min = hsbColor.b - dif;
float h = hsbColor.h * 360f / 255f;
if (h < 60f)
{
r = max;
g = h * dif / 60f + min;
b = min;
}
else if (h < 120f)
{
r = -(h - 120f) * dif / 60f + min;
g = max;
b = min;
}
else if (h < 180f)
{
r = min;
g = max;
b = (h - 120f) * dif / 60f + min;
}
else if (h < 240f)
{
r = min;
g = -(h - 240f) * dif / 60f + min;
b = max;
}
else if (h < 300f)
{
r = (h - 240f) * dif / 60f + min;
g = min;
b = max;
}
else if (h <= 360f)
{
r = max;
g = min;
b = -(h - 360f) * dif / 60 + min;
}
else
{
r = 0;
g = 0;
b = 0;
}
}
return(Color.FromArgb
(
hsbColor.a,
(int)Math.Round(Math.Min(Math.Max(r, 0), 255)),
(int)Math.Round(Math.Min(Math.Max(g, 0), 255)),
(int)Math.Round(Math.Min(Math.Max(b, 0), 255))
));
}
